There are numerous ways that two electrically isolated devices can communicate. Radio frequency (RF) communications is one of the most common communication methods. However, for close proximity communication, RF communication is not desirable in light of the bandwidth requirements, power consumption, and design complexity associated with RF system design.
Infrared (IR) communication presents another possible communication method, wherein infrared light is used to communicate digital information. Compared to RF, IR is more suitable for proximity communications, but the transceiver aperture must be kept relatively free of blockage (e.g. dust and dirt build up). As a result, IR communication is not generally suitable for outdoor applications. To overcome such blockages, the output power of the IR transmitter can be increased which increases overall power consumption. Additionally, IR diodes and transistors, whether packaged together or separate, have some amount of height, which may not be ideal for certain communication devices.
Magnetic coupling offers another communication alternative. This form of communication uses magnetic fields to allow two devices that are magnetically coupled to communicate. The magnetic fields are typically generated by driving coils. The generated magnetic field is picked up by a pick-up coil on the receiving circuitry. For fast communications, the coils have to be small to reduce the coil charging time. However, this results in a weak magnetic field generated by the small coil, meaning that: a) effective communications may only be possible if the generator and pick-up coil are placed very near each other, beyond practical limits, b) the receiver circuitry of the pick up coil has be extremely sensitive, or c) there must be a set of separate generator and pick-up coil in each transceiver where the pick-up coil can be made bigger to be more effective, but this means that the coils take up additional space in each device. Bigger coils and/or more power is needed to generate larger magnetic fields to meet the above limitations, but this requires more device space and/or more power consumption.
A need exists for a system and method that allows for close-proximity communication between devices without requiring high power consumption or significant device space.